1. Field of the Invention
The present invention relates to an electron-emitting element, a method of making the same, and an electronic device such as field-emission display (FED), field-emission microscope (FEM), or the like which uses an electron-emitting element.
2. Related Background Art
With the recent advance in minute processing in semiconductor technology, the field of vacuum microelectronics has been rapidly developing. Consequently, as an electronic device for the next generation having a function of displaying or the like, the field-emission display (FED) has come into expectation. It is due to the fact that, unlike the conventional CRT displays, the FED has two-dimensionally arranged minute electrodes which function as field-emission type electron-emitting elements, so that it is unnecessary to deflect and converge the electrons in principle, whereby the display can be easily made thinner or flatter.
As a material used for such a minute electrode, diamond has recently been noticed. It is due to the fact that diamond has a very advantageous characteristic as an electron-emitting device, i.e., its electron affinity is negative. Accordingly, when diamond is pointed and employed as a minute electrode, it can emit electrons at a low voltage.
As a method of making pointed diamond, the following methods have been reported. For example, Japanese Patent Application Laid-Open No. 7-94077 discloses that, when a partially masked diamond substrate is etched, pointed diamond projecting from the substrate surface can be obtained. Also, NEW DIAMOND, 39, vol. 11, No. 4, pp. 24-25 (1995), reports that an isolated particle of diamond having a pointed form with no grain boundary is obtained as being oriented to (111) surface on a Cu substrate.